Profile sections for plate-like composite elements

ABSTRACT

The invention concerns profile sections for reinforcing or finishing the edges of plate-like composite elements, said sections comprising a core layer (31) and two cover layers (11, 21). The invention further concerns composite elements produced thereby and a method of producing these composite elements. The profile sections consist of at least two parallel legs (1, 2) and a connection web (4) and comprise an abutment surface (3) for the core layer (31). Disposed between the edges (5, 6) of the abutment surface (3) and the connection web (4) are open channels (7, 8) through which the air located between the cover layers (11, 21) and the core layer (31) and/or the profile section legs when the composite element is bonded can escape such that a bubble-free bonded connection is attained over the entire surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to new profiles for use as reinforcementor bordering of sheetlike composite elements ("sandwich elements"), tothe composite elements constructed with these profiles, and to a processfor producing these composite elements.

2. Background Art

Sheetlike composite elements, consisting most simply of a core layer andtwo top layers connected by this core layer and surface-bonded to it,the material employed for the core layer generally being a rigid foamand the material employed for the top layers generally being sheet metalor another material having tensile strength, are increasingly used as aconstruction material owing to their low weight and advantageousmechanical properties. In transportation in particular, i.e. in theconstruction of commercial vehicles of all kinds, for example lorries,buses or rail vehicles, or of freight containers, they are employed inparticular for floor, wall and ceiling constructions.

Here and in the text below the term "sheetlike" composite elements doesnot refer exclusively to flat components but also to curved parts, suchas the roofs of rail carriages, whose form can essentially be describedby cylindrical areas or by a combination of flat and cylindrical areas.

Owing to the limited stability of these composite elements in the caseof locally concentrated stresses, especially as a result of forcesacting in a punctiform or linear manner perpendicularly to the layersand above all in the border region, it is frequently necessary toinstall reinforcing elements at the appropriate points, i.e. placeswhere fixing elements need to be attached to join the composite elementsto one another, to other load-bearing structural components or tomechanically stressed fitments (e.g. seats, holding rails or luggageracks in public transport vehicles), these reinforcing elements being inthe form of profiles of metal or another high-strength material.

The term border profiles is used here and below to denote those profileswhich form the border of a composite element or which join two compositeelements to one another at their borders (joining profiles). Insertprofiles denote those profiles which for reinforcement purposes arearranged in the interior of the composite element, the core layer beinginterrupted at the appropriate point and the top layers running on overthe profile.

Both the core layer and the top layers can be homogeneous or can beconstructed in turn from a plurality of layers. For example, areinforcing layer can be embedded in a core layer of foam, or a toplayer may, for example, consist of plywood.

The composite elements are normally produced by coating one or bothsides of the top layers (consisting for example of sheet aluminium), thecore material and the insert or border profiles--having simplecross-sections, in general, usual square profiles--with an adhesive,initially on the boundary faces. Subsequently, the individual parts arebrought together in the desired geometric arrangement in a bonding mouldand surface-bonded by external pressure. The external pressure employedis frequently the atmospheric air pressure, the bonding mould beingcovered with an airtight film and evacuated. In order to obtain a goodbond and a flawless surface, it is necessary to allow the air betweenthe layers, and also any excess adhesive, to escape as fully aspossible. To this end the core layer is often provided with a relativelylarge number of parallel slots or grooves through which the air is ableto pass to the border of the composite element. When using customarycommercial profiles, for example in U, Z or H cross-section, however,this is no longer ensured. Indeed, in order to achieve high mechanicalstability these profiles must be bonded over their entire area both tothe top layers and to the narrow side of the core layer, leaving no roomin between for the escape of air. Consequently, the production ofcomposite elements of large surface area in particular is oftenaccompanied, especially in the region of the profiles, by the formationof air bubbles, which may considerably impair the mechanical propertiesand may also be visible on the exterior of the component.

BROAD DESCRIPTION OF THE INVENTION

The object of the present invention, therefore, was to provide newprofiles which do not give rise to these disadvantageous phenomena inthe production of sheetlike composite elements.

This object is achieved in accordance with the invention by the profilesaccording to Patent claim 1. In their simplest form, the profilesconsist of two essentially parallel arms whose inside or outside servesas a bearing surface for in each case one of the top layers, of aconnecting crosspiece between the arms, and of a bearing surface for thenarrow side of the core layer. The geometric spacing of the arms, i.e.the distance between the planes defined by the bearing surfaces for thetop layers, corresponds to the distance between the top layers of thecomposite elements that are to be produced with the profile; the bearingsurface for the core layer lies between these planes. Depending on therelative position of the arms to one another and to the connectingcrosspiece, the profile may have an essentially U-, Z- or H-shapedcross-section, although transitional variants of course are alsopossible.

Combinations of these basic forms are also possible by the presence oftwo or more connecting crosspieces between the arms. One preferred form,for example, contains two opposing bearing surfaces for the core layerand is therefore particularly suitable as an insert or joining profile.

The core-layer bearing surface, which is preferably perpendicular to thearms of the profile, is in accordance with the invention not--as with asimple U, Z or H profile--directly adjacent to these arms but instead isseparated from the connecting crosspiece by at least one spacer whichextends in the longitudinal direction of the profile. In thisarrangement, the spacer (or, in the case of a plurality of spacers, eachouter spacer) does not adjoin an outer border of the core-layer bearingsurface but is set back from it, thus forming a channel which extends inthe longitudinal direction of the profile. The core-layer bearingsurface is designed, furthermore, so that between its outer(longitudinal) borders and the bearing surfaces for the top layers, andbetween the planes defined by these surfaces, there remains in each casean interspace extending in the longitudinal direction of the profile.The interspaces are preferably continuous over the entire length of theprofile but may also be interrupted at short sections as a result, forexample, of the corresponding design of the borders. As a result ofthis, the bearing surface for the core layer does not with its bordersform an airtight seal to the top layers in the installed state; instead,there remains in each case a continuous or interrupted gap whichcommunicates with at least one of the above-described channels extendingin the longitudinal direction of the profile. The profile preferablycontains a corresponding channel for each gap, it being possible for theprofile also to include, if desired, additional, open or closedchannels. This system of gaps and channels enables both air and excessadhesive to escape without problems during the manufacture of thecomposite elements. Because of the offset of each spacer the channelshave a sufficiently large cross-section which even in long profilesallows rapid escape of air and which cannot be blocked by, for instance,the ingress of excess adhesive. Especially in the case of vacuumbonding, this achieves improved evacuation of the interior of thecomponent, which also enhances the strength of the adhesive surfacebonds between core layer and top layers.

The bearing surfaces for the top layers and/or the core layer arepreferably provided with slots or grooves. When the composite elementsare bonded, these slots or grooves are able to accommodate some of theadhesive, and possibly also material of the top layer if the latter isreadily deformable. This produces a certain intermeshing effect or apositive connection, which increases the strength of the adhesive bond.For mechanical and manufacturing reasons, these slots or groovespreferably extend in the longitudinal direction of the profile.

In one particularly preferred design the bearing surfaces for the toplayers are on the sides of the arms that are remote from the connectingcrosspiece, i.e. on the outsides of the profile. In the installed statethey contact the top layers of the composite element from inside, thedistance between the bearing surfaces corresponding to the thickness ofthe core layer. Profiles of this design are suitable both as insertprofiles in the interior of the composite element and as borderprofiles.

In another preferred design the bearing surfaces for the top layers areon the sides of the arms that face the connecting crosspiece, i.e. onthe insides of the profile. In the installed state they contact the toplayers of the composite element from outside, the distance between thebearing surfaces corresponding to the overall thickness of the compositeelement. Profiles of this design are suitable as border profiles (withU- or H-shaped cross-section) or as joining profiles for two compositeelements (with H-shaped cross-section).

In a further design, the bearing surface for one top layer is on theside of one arm that faces the connecting crosspiece and the bearingsurface for the other top layer is on that side of the other arm that isremote from the connecting crosspiece. In the installed state,therefore, one top layer is contacted from outside and the other frominside. The distance between the bearing surfaces corresponds to thethickness of the core layer plus one top layer. Profiles of this designare suitable as border profiles, especially if the composite element isto be mounted by one side on a support frame and is to form a smoothsurface on the other side. The composite element can then be fasteneddirectly to the border profile.

To facilitate the assembly of the finished composite element and/or toimprove its mechanical properties it is possible to provide borderprofiles according to the invention, outside the bearing surfaces forthe core and top layers, with spacing and/or bearing elements, forexample with formed-on spacer strips. It is likewise possible to provideholding elements which are suitable for receiving the spacing and/orbearing elements. The latter can then, for example, consist of adifferent material from the profile itself.

For this purpose, in one particularly preferred embodiment groovesextending in the longitudinal direction are made in the profiles, intowhich grooves, for example, it is possible to insert spacer strips ofelastic material or--given appropriate groove cross-section--fasteningnuts.

The profiles, furthermore, may also include additional channels for thelaying of lines of all kinds, these channels possibly also servingthemselves as lines for air or a heating medium, for example.

Examples of suitable materials for the profiles are metals, especiallysteel or aluminium (alloys) or else solid plastics. They can be producedby techniques customary for the material, for example by the bending orrolling of metal sheets, by milling from solid material or by thecompression-moulding or extrusion of materials capable of plasticdeformation. Preferably they are produced by extrusion of aluminiumalloys. This technique is particularly suitable for producing complexprofile cross-sections in one operation without additional machining.

A further subject of the invention are the sheetlike composite elementsconsisting of at least one core layer, two top layers connected to it atthe surface, and at least one profile according to the invention.Materials suitable for the core layer are in principle all materialscustomary in this technical field, especially closed-cell rigid foams,for example those based on polyvinyl chloride, polyolefins orpolyurethanes. Also suitable are natural lightweight constructionmaterials, such as cork or balsa wood, for example, or inorganicmaterials, such as foam glass, for example. Examples of suitable toplayers are metal sheets, especially those of steel alloys or aluminiumalloys, plastic films or sheets, especially with fibre reinforcement,and also materials such as kraft paper, chipboard or plywood. Thesurface connection between core and top layers is preferably an adhesivebond, although depending on the combination of materials other types ofconnection may be suitable, for example a welded bond.

The core layer is preferably provided on at least one of the surfaceswhich are bonded to the top layers, with a system of slots or groovesthat are essentially parallel to one another. They are preferablyarranged so that they form an angle with the longitudinal direction ofthe profile or profiles.

In one preferred embodiment of the composite elements the lattercomprise a border profile according to the invention, and at least oneof the top layers is bent as a border finish around a correspondinglydesigned edge of the border profile, preferably by an angle of fromabout 90° to about 180°. This both improves the tensile strength of theconnection of the top layer to the profile and makes for a visuallyappealing border, and on the installed composite element the profile isout of sight.

The composite elements are produced in accordance with the invention byproviding the top layers and/or the prefabricated core layer on at leastone side of the intended contact surfaces with an adhesive, bringingtogether the said layer or layers in the intended arrangement with oneanother and with the profile (5), which may also have been coated withadhesive, and bonding the components to one another by means of externalpressure. The entire arrangement can, if desired, be heated in order toactivate and/or bring about faster curing of the adhesive.

In order to avoid inclusions of air in the course of bonding, and tointeract with the channels that in accordance with the invention arepresent in the profiles, it is advantageous to use a core layer which isprovided, on one or both of its surfaces to be bonded to the top layers,with a system of slots or grooves essentially parallel to one another.The direction of these slots or grooves judiciously forms an angle withthe longitudinal direction of the profile or profiles, this anglepreferably being approximately a right angle.

The external pressure employed in bonding is preferably the atmosphericair pressure, the air being removed by suction from the interspacesbetween the layers and so a (partial) vacuum is generated.

This procedure is preferably realized such that the prepared componentsof the composite element are arranged on a solid substrate and coveredwith a flexible airtight film. Then the space containing the compositeelement, enclosed by the substrate and the film, is evacuated, so thatthe air escapes from the interspaces through the channels of the profileor profiles, and the external air pressure compresses the entirearrangement.

To produce non-planar composite elements such as curved vehicle roofs,for example, it is advantageous to use an appropriately shapedsubstrate.

In order to achieve a tidy border finish and increased strength, atleast one of the top layers is preferably dimensioned so that afterbonding it projects over one outer edge of a border profile. Theprojecting portion is then bent around this edge, preferably by an angleof from about 90° to about 180°.

The profiles according to the invention have been used to produce, forexample, composite elements measuring 2.2×12.5 m². Relative to thecomposite elements of the same dimensions produced with conventionalprofiles, the former elements had considerably better mechanicalproperties, as could be demonstrated, inter alia, by means of peeltests.

DETAILED DESCRIPTION OF THE DRAWINGS

The drawings depict, diagrammatically, some exemplary embodiments of theprofiles according to the invention and of the composite elementsproduced therewith; specifically,

FIG. 1 shows a cross-section through a U-shaped border profile

FIG. 2 shows a cross-section through the border part of a compositeelement fitted with a U-shaped border profile

FIG. 3 shows a cross-section through a composite element with insertprofile

FIG. 4 shows a cross-section through the edge part of a compositeelement with a Z-shaped border profile

FIG. 5 shows a cross-section through the border part of a compositeelement with a top layer bent around the outer edge of the borderprofile

FIG. 6 shows a cross-section through the border part of a compositeelement with a fastening groove made in the border profile

FIG. 7 shows a cross-section through the arrangement for bonding thecomponents of a composite element

FIG. 8 shows a perspective diagram of the components of a compositeelement.

FIG. 9 shows a perspective diagram of the components of anothercomposite.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 shows the cross-section through an essentially U-shaped borderprofile having two arms 1, 2 whose outsides serve as bearing surfacesfor the top layers and define the planes 1', 2', having a bearingsurface 3 with borders 5, 6 for the core layer, having a connectingcrosspiece 4, two spacers 41, two open channels 7, 8, and slots 9 madein the bearing surfaces.

FIG. 2 shows the same border profile as FIG. 1, but in the installedstate with the top layers 11, 21 and the core layer 31. At the openchannels 7, 8 it is possible to see the interspaces between the toplayers 11, 21 and the borders 5, 6 of the bearing surface 3 for the corelayer 31.

FIG. 3 shows, in cross-section, an insert profile in the installedstate. The profile has two opposing bearing surfaces 3 for in each caseone core layer 31 and is covered over by the top layers 11, 21, so thatin a plan view onto the composite element it is out of sight. Theprofile corresponds to a mirror-image doubling of the profile in FIG. 1.

FIG. 4 shows a cross-sectionally Z-shaped border profile in theinstalled state. The bearing surface of the arm 41 for the top layer 11is on the side remote from the connection crosspiece 4, while that ofthe arm 42 for the top layer 21 is on the side facing the connectingcrosspiece. In the regions between the arms 41, 42 and the core layer31, the open channels 7, 8 are shown. With the free surfaces of the arms41, 42 and of the connecting crosspiece 4, the composite element is ableto lie, for example, on other structural components without exertingstress on the top layers 11, 21. One top layer, 11, finishes with theouter edge of the arm 41, the other top layer, 21, finishing flush withthe core layer 31.

FIG. 5 shows in principle the same arrangement as FIG. 4, except thatone top layer, 11, is bent with its border 12 by about 180° around theouter edge of the arm 51, and the other top layer, 21, continues up to ashoulder in the region of the channel 8.

FIG. 6 shows a similar arrangement as FIG. 5, although additionally agroove 22 is made in the free surface of the arm 62, it being possibleto insert, for example, an elastic seal into this groove.

FIG. 7 shows diagrammatically the adhesive bonding of core layer, toplayer and border profiles as in FIG. 4 to form a composite element. Theindividual parts are arranged on a solid substrate 23 and covered with aflexible airtight film 13. The space between substrate and film isevacuated so that the external air pressure compresses the arrangementand the air present between the individual parts is able to escapethrough the channels 7, 8.

FIG. 8 shows in perspective the individual parts of a composite element,namely a border profile as in FIG. 4 with the two arms 81, 82 and thebearing surface 3 for the core layer, the top layers 11, 21 and the corelayer 31. Slots 32 are made on the top and bottom side of the core layer31, only one of each of these slots being shown in the diagram. Theslots 32 extend approximately at right angles to the longitudinaldirection of the border profile.

In FIG. 9, the following reference characters (see FIG. 4) are:

3 bearing surface for the core layers

4 connecting crosspiece

7,8 open channel

9 slot

35 arm for the top layer 11

36 arm for the top layer 21

37 bearing surface of the arm 36

38 bearing surface of the arm 35

41 spacer.

What is claimed is:
 1. A sheetlike composite element comprising a coreelement, the core element having opposing spaced outer surfaces, anouter layer which is connected to one of the opposing spaced outersurfaces of the core element, another outer layer which is connected tothe other opposing spaced outer surface of the core element, and aprofile for the reinforcement of the sheetlike composite element, theprofile contacting said core element, the profile having two essentiallyparallel arms, which act as bearing surfaces selected from the groupconsisting of inner bearing surfaces and outer bearing surfaces, for thetwo outer layers and whose geometric spacing is at least as great as thedistance between the two outer layers, having a further bearing surfacefor non-outer, narrow side of the core element, which further bearingsurface is arranged between planes defined by said parallel arms bearingsurfaces, and having at least one continuous connecting crosspiecebetween said parallel arms, and forming with arms a shaped arrangementselected from at least one member of the group consisting of anessentially U-, Z- and H-shaped arrangement in cross-section in thelatitudinal direction of the profile, and said further bearing surfacehaving outer extensions in portion which contact said core element, thefurther bearing surface for said narrow side of the core element isseparated from said at least one connecting crosspiece by at least onespacer, which extends between said at least one connecting crosspieceand said further bearing surface, said at least one spacer beingconnected to said further bearing surface so as to provide said outerextensions of said further bearing surface, and an interspace selectedfrom the group consisting of a continuous interspace and an interruptedinterspaces extending in the longitudinal direction of the profile beingpresent between the parallel arms bearing surfaces for the outer layersand the planes defined by the parallel arms bearing surfaces and outerborders of the further bearing surface for the core element, saidinterspace being in communication with at least one channel whichextends in the longitudinal direction of the profile.
 2. The sheetlikecomposite element according to claim 1, wherein slots or grooves aremade in said further bearing surface or the parallel arms bearingsurfaces for the core, respectively.
 3. The sheetlike composite elementaccording to claim 2, wherein the slots or grooves extend in thelongitudinal direction of the profile.
 4. The sheetlike compositeelement according to claim 3, wherein the parallel arms bearing surfacesfor the outer layers are on the sides of the parallel arms that areremote from the continuous connecting crosspiece.
 5. The sheetlikecomposite element according to claim 1, wherein the core element isbonded to one of the outer layers, and at least one of the bond surfacesis provided with slots or grooves which are essentially parallel to oneanother and whose direction forms an angle with the longitudinaldirection of the profile.
 6. The sheetlike composite element accordingto claim 1, wherein the parallel arms bearing surfaces for the outerlayers are on the sides of the parallel arms that are remote from thecontinuous connecting crosspiece.
 7. A sheetlike composite elementcomprising a core element, the core element having opposed spaced outersurfaces, an outer layer which is connected to one of the opposingspaced outer surfaces of the core element, another outer layer which isconnected to the other opposing spaced outer surface of the coreelement, and a profile for the bordering of the sheetlike compositeelement, the profile contacting said core element, the profile havingtwo essentially parallel arms, which act as bearing surfaces selectedfrom the group consisting of inner bearing surfaces and outer bearingsurfaces, for the two outer layers and whose geometric spacing is atleast as great as the distance between the two outer layers, having afurther bearing surface for non-outer, narrow side of the core element,which further bearing surface is arranged between planes defined by saidparallel arms bearing surfaces, and having at least one continuousconnecting crosspiece between said parallel arms, and forming with armsa shaped arrangement selected from at least one member of the group ofan essentially U-, Z- and H-shaped arrangement in cross-section in thelatitudinal direction of the profile, and said further bearing surfacehaving outer extensions in portion which contact said core element, thefurther bearing surface for said narrow side of the core element isseparated from said at least one connecting crosspiece by at least onespacer, which extends between said at least one connecting crosspieceand said further bearing surface, said at least one spacer beingconnected to said further bearing surface so as to provide said outerextensions of said further bearing surface, and an interspace selectedfrom the group consisting of a continuous interspace and an interruptedinterspace, extending in the longitudinal direction of the profile beingpresent between the parallel arms bearing surfaces for the outer layersand the planes defined by the parallel arms bearing surfaces for theouter layers and the planes defined by the parallel arms bearingsurfaces and outer borders of the further bearing surface for the coreelement, said interspace being in communication with at least onechannel which extends in the longitudinal direction of the profile. 8.The sheetlike composite element according to claim 7, wherein theprofile is a border profile and the parallel arms bearing surfaces forthe outer layers are on the sides of the parallel arms that face thecontinuous connecting crosspiece.
 9. The sheetlike composite elementaccording to claim 7, wherein the profile is a border profile and one ofthe parallel arms bearing surfaces for the outer layers is on that sideof one parallel arm that faces the continuous connecting crosspiece andthe other is on that side of the other parallel arm that is remote fromthe continuous connecting crosspiece.
 10. The sheetlike compositeelement according to claim 7, wherein the profile is a border profileand outside of the further bearing surface and the parallel arms bearingsurfaces for the core element and outer layer or layers, respectively,there is at least one spacing element or bearing element or a holdingelement suitable for receiving the at least one spacing element orbearing element.
 11. The sheetlike composite element according to claim10, wherein the profile is a border profile and the holding element isat least one groove in the profile in the longitudinal direction of theprofile.
 12. The sheetlike composite element according to claim 7,wherein the profile is a border profile and, as a border finish, atleast one of the outer layers is bent around a correspondingly designededge of the border profile.
 13. The sheetlike composite elementaccording to claim 7, wherein the profile is a border profile and, as aborder finish, at least one of the outer layers is bent around acorrespondingly designed edge of the border profile.
 14. The sheetlikecomposite element according to claim 7, wherein the profile is a borderprofile and the bearing surfaces for the outer layers are on the sidesof the parallel arms that face the continuous connecting crosspiece. 15.The sheetlike composite element according to claim 7 wherein the profileis a border profile and one of the bearing surfaces for the outer layersis on that side of one parallel arm that faces the continuous connectingcrosspiece and the other is on that side of the other parallel arm thatis remote from the continuous connecting crosspiece.
 16. The sheetlikecomposite element according to claim 7, wherein the profile is a borderprofile outside of the at least one further bearing surface and theparallel arms bearing surfaces for the one or two core elements andouter layer or layers, respectively, there is at least one spacingelement or bearing element or a holding element suitable for receivingthe at least one spacing element or bearing element.
 17. A sheetlikecomposite element comprising two core elements, each core element havingopposed spaced outer surfaces, an outer layer which is connected to oneof the opposing spaced outer surfaces of each of the two core elements,another outer layer which is connected to the other opposing spacedouter surface of each of the two core elements, and a profile for thereinforcement of the sheetlike composite element, said profile havingtwo opposed ends, the opposed ends of the profile contacting said twocore elements, the profile having two essentially parallel arms, whichact as bearing surfaces selected from the group consisting of innerbearing surfaces and outer bearing surfaces, for the two outer layersand whose geometric spacing is at least as great as the distance betweenthe two outer layers, having two further bearing surfaces, each for anon-outer, narrow side of each of the core elements, which two furtherbearing surfaces are arranged between planes defined by said parallelarms bearing surfaces, and each further bearing surface having at leastone continuous connecting crosspiece between said parallel arms, andforming with arms a shaped arrangement selected from at least one memberof the group of an essentially U-, Z- and H-shaped arrangement incross-section in the latitudinal direction of the profile, and each ofsaid further bearing surfaces having outer extensions in portion whichcontact one of said core elements, each of the further bearing surfacesfor said narrow side of one of the core elements is separated from saidat least one connecting crosspiece by at least one spacer, which extendsbetween said at least one connecting crosspiece and one of the saidfurther bearing surfaces, said at least one spacer being connected tothe one of the further bearing surfaces so as to provide said outerextensions of the one of the further bearing surfaces, and, on eachopposed end of the profile, an interspace selected from the groupconsisting of a continuous interspace and an interrupted interspace,extending in the longitudinal direction of the profile being presentbetween the parallel arms bearing surfaces for the outer layers and theplanes defined by the parallel arms bearing surfaces for the outerlayers and the planes defined by the parallel arms bearing surfaces andouter borders of each of the further bearing surfaces for each of thecore elements, each of said interspaces being in communication with atleast one channel which extends in the longitudinal direction of theprofile.
 18. A sheetlike composite element comprising two core elements,each core element having opposed spaced outer surfaces, an outer layerwhich is connected to one of the opposing spaced outer surfaces of eachof the two core elements, another outer layer which is connected to theother opposing spaced outer surface of each the two core elements, and aprofile for the bordering of the sheetlike composite element, saidprofile having two opposed ends, the opposed ends of the profilecontacting said two core elements, the profile having two essentiallyparallel arms, which act as bearing surfaces selected from the groupconsisting of inner bearing surfaces and outer bearing surfaces, for thetwo outer layers and whose geometric spacing is at least as great as thedistance between the two outer layers, having two further bearingsurfaces, each for a non-outer, narrow side of each of the coreelements, which two further bearing surfaces are arranged between planesdefined by said parallel arms bearing surfaces, and each further bearingsurface having at least one continuous connecting crosspiece betweensaid parallel arms, and forming with arms a shaped arrangement selectedfrom at least one member of the group of an essentially U-, Z- andH-shaped arrangement in cross-section in the latitudinal direction ofthe profile, and each of said further bearing surfaces having outerextensions in portion which contact one of said core elements, each ofthe further bearing surfaces for said narrow side of one of the coreelements is separated from said at least one connecting crosspiece by atleast one spacer, which extends between said at least one connectingcrosspiece and the one of the further bearing surfaces, said at leastone spacer being connected to the one of the further bearing surfaces soas to provide said outer extensions of the one of the further bearingsurfaces, and, on each opposed end of the profile, an interspaceselected from the group consisting of a continuous interspace and aninterrupted interspace, extending in the longitudinal direction of theprofile being present between the parallel arms bearing surfaces for theouter layers and the planes defined by the parallel arms bearingsurfaces for the outer layers and the planes defined by the parallelarms bearing surfaces and outer borders of each of the further bearingsurfaces for each of the core elements, each of said interspaces beingin communication with at least one channel which extends in thelongitudinal direction of the profile.